What Grows There :: Hugh Conlon, Horticulturalist, Garden Advisor, and Photographer

Leather Flower Clematis- Hot Pink Summer Flowering Vine

Posted by Hugh on June 11th, 2011

Leather flower (Clematis glaucophylla)

Leather flower (Clematis glaucophylla) is native to moist woodlands in the Southeastern U.S. This lovely flowering vine is covered with one inch hot pink flowers tipped in yellow. The solitary, 1- inch bell shaped flowers are on 6- inch long stalks which reach out for support. It is called “leather flower” because the petals are thickened almost like a thin banana peel.

A mature vine may open a hundred or more flowers at one time. Leather flower blooms from June to October if kept moist. Its clematis seed heads are uniquely showy. Leather flower is also a hummingbird magnet.

Plant it in good composted soil with adequate moisture and partial sunlight. In zone 6-a (eastern PA) it grows in full sun, and moving further south, provide more shade. Let it grow on a trellis or along a fence or rail. Allow it to weave through a tree or ramble at will. The vine clings by wrapping its leaf stems (petioles) around the supporting structure.

A 2 -year established leather flower grows 12 – 15 feet. Flowering occurs on new growth only. Aggressively prune a dormant vine in late winter (Pruning Group 3), cutting back each main branch to two strong buds close to the ground.

Availability: Sunlight Gardens in Andersonville, TN. Order through the website: www.sunlightgardens.com

Bagworms Can Devastate Evergreens

Posted by Hugh on June 8th, 2011

Bagworm on conifer- photo by Alan Windham

Bagworms feed on more than 128 species of plants, including junipers, cedars, arborvitae and white pine. More than one year of severe defoliation will kill a formerly healthy specimen. Bagworms have one generation per year. Eggs usually hatch in mid to late May across the Southern Appalachian region (USDA zones 6 and 7).

Upon hatching, the young larvae crawl out of the bottom of the bag and begin eating plant foliage. Maturing larvae can do considerable defoliation during early summer. As the worms age, they construct a silken shelter over their body and are more difficult they are to kill.

Bagworms’ carrot-shaped bag is constructed of bits of material from the plant upon which it’s feeding and expands as the bagworm grows. The bag is carried wherever the worm goes. When disturbed, the bagworm merely pulls its head back into its bag for protection.

Insecticides should be applied when the bagworms are small, but after all have hatched by early June. After mid-June pesticide control is too late. Complete spray coverage is essential. Carbaryl (Sevin), Bt (Dipel), Malathion, acephate (Orthene), and pyrethroids like bifenthrin (Talstar), cyfluthrin, and permethrin), and spinosad (Conserve SC) are highly recommended. Spinosad controls the hard to kill older bagworms.

Calliope™ Dark Red Geranium- One of the Best

Posted by Hugh on June 4th, 2011

Calliope Dark Red geranium

Garden performance is very important. Calliope™ Dark Red geraniums have it!! Calliope geraniums are interspecific hybrids with zonal-type leaves and huge vibrant red flowers. Plant breeders crossed ivy geraniums (the kind commonly used as hanging baskets) and zonal geraniums (found growing in pots, window boxes, and as bedding plants).

Calliope is a vigorous grower with a mounding to semi-trailing growth habit. A local East TN grower describes Calliope as “a geranium on steroids”. Newest in the Calliope series is ‘Scarlet Fire’ with bright red blooms. Both cultivars branch exceptionally well.

Calliope combines well with yellow and blue flowering annuals. Calliope demonstrates excellent heat tolerance in the landscape. In the Southern Appalachian region (USDA zones 6 and 7). Locate Calliope where it receives full morning sunlight and partial shade in the afternoon. Summer watering and feeding container grown geraniums are crucial.

Calliope Dark Red is a moderate to heavy feeder. Feed plant(s) every two weeks with a soluble plant food such as 20-10-20 (or equivalent) to soil or potting medium. Alternatively, you may feed geraniums with a granular slow-release fertilizer every four to six weeks.

Pinching off old spent blooms at the base of the stem encourages continuous flowering and plant growth. Pinching also reduces the chances of floral and leaf spot diseases.

Stewartia- A Tree for All Seasons

Posted by Hugh on June 1st, 2011

Lovely Japanese stewartia at Biltmore Estate in Asheville, NC

June flowering stewartia

Japanese stewartia (Stewartia pseudocamellia) is a truly beautiful 20-30 foot small tree or multi-trunked shrub. Stewartia may be finicky to grow, but a great plant nonetheless. Although rarely seen in U.S. gardens, Japanese stewartia is the most commonly grown of the six stewartia species. All are winter hardy in the Southern Appalachian region (USDA zones 6 and 7).

Visually, stewartia provides four seasons of ornamental beauty. Lovely 2 to 2 ½ inch camellia-like white flowers appear in early June and are in bloom for 2 – 3 weeks. The 3 – 4 inch blemish-free green summer foliage turns yellow and/or crimson red in mid- autumn, depending on its location. Its patchwork mottled bark becomes more attractive with age.

The trick to growing stewartia is selecting a proper site. Stewartia may flourish for many years if the soil drainage and sunlight exposure are near perfect. Japanese stewartia grows similar to flowering dogwood (Cornus florida), requiring a compost rich, acidic pH and almost perfectly drained soil.

Filtered all-day sunlight or six hours of morning /early afternoon sunlight is ideal. Prolonged periods of scorching summer heat and low rainfall may be fatal to Japanese stewartia. Irrigate to cool and refresh the tree(s) and keep adequately mulched.

Does Mulch Attract Termites?

Posted by Hugh on May 29th, 2011

Recently mulched shrubs

Mulching, in itself, does not attract termites to your home. That’s the conclusion of two university studies. Soil moisture appears to be the key factor that attracts termites to the home. The subterranean termites found in scattered, localized areas are routinely found in wood chip mulch.

While landscape mulches are good for woody and herbaceous plants, they’re admittedly favorable for termites and other insects as well. Soil moisture favors termite exploration, tunneling and feeding.

University of Maryland entomologists found that termite populations were detected beneath many kinds of mulches, including eucalyptus, hardwood, pine bark, and pea gravel. However, termite activity was significantly higher beneath the gravel mulch. Scientists concluded that termite activity is more about a suitable habitat.

A University of Florida study reported that termites can be found in mulch, but their survival is poor. Why? – because the ability of termites to survive the chipping process that manufactures mulch is not good. Mulch-fed termites suffer significantly lower survivorship.

Overall recommendations: Keep mulch 12-18 inches away from the house foundation. Termites do need a cellulose materials like mulch to feed on. Always watch for signs of termites and their location (activity) around your home.

Wild Epaulette Tree Can Be Tamed

Posted by Hugh on May 26th, 2011

Epaulette tree

Epaulette tree (Pterostyrax hispida) is a small flowering tree which quickly grows to a mature height of 20—25 feet. Winter hardiness here in the Southern Appalachian region (USDA zones 6 and 7) is no problem. A newly planted tree grows an average of 15-18 inches per year and blooms early.

Epaulette prospers in a moist well-drained soil of moderate acidity (pH 5.5 to 6.5) and in full to partial (6 hours minimum) sunlight. Established trees exhibit excellent heat and drought tolerances. Troubles with diseases and insects are not issues.

In mid- to late May, the oft-white wisteria-like floral panicles emerge, a full two weeks following the appearance of the bold 4 – 7 inch long leaves. Clusters of bell-shaped lemony scented flowers create a good showing as pendulous 5-10 inch long panicles. Many stay hidden beneath the coarse foliage canopy. Individual fringed florets measure small, 1/3 inches in diameter or less. Stringy threads of bristly seed clusters follow and persist well through the winter months, offering little in landscape interest.

Epaulette has a strong propensity to root sucker. It demands a committed gardener to steadfastly remove unwanted suckers and lower branches. Eventually, you can tame the wild epaulette into a handsome small specimen tree in garden or patio areas.

Is Paulownia Invasive?

Posted by Hugh on May 24th, 2011

Paulownia uninvited!!

Paulownia or Empress tree (Paulownia tomentosa) is a medium to large 30-50 foot tree. It is extremely fast growing, brittle wooded tree, as much as 4 feet per year. Across the Southern Appalachian region (USDA zones 6 and 7), the large pale violet flowers of paulownia are easily visible in May, perched on branch tips.

Its enormous 10-12 inch large medium green leaves are pushing out at the same time. The leaves dump considerable litter beneath the tree in the fall. Fall foliage color is of little importance.

Paulownia is an exotic from China which many plant experts have labelled “invasive”. A large paulownia tree produces many thousands of viable seeds which are dispersed by wind. The seeds are very susceptible to damping off disease (Pythium) and many do not survive. Seeds do germinate on “sterile” soil such as recently cleared ground and burned areas.

Paulownia is rarely seen in open fields already containing vegetation, compared to other serious invasives such as tree-of-heaven, privet, honeysuckle, et.al. It may grow on the edge of forests, but does not survive or compete in woodland shade.

Paulownia wood is highly prized by the Japanese for furniture, cooking utensils, owls, etc. There are several growers in the Southeastern U.S. who grow the fast growing paulownia wood for its export value.

Yellowwood Not Every Year Bloomer

Posted by Hugh on May 22nd, 2011

Yellowwood's gray beech-like bark

American yellowwood (Cladrastis kentukea) is a medium-sized flowering tree. In the month of May, a beautiful yellowwood tree is in bloom somewhere in the Southern Appalachian region (USDA zone 6 and 7). The 1- 1 1/2 inch white pea blossoms comprise the 8-14 inch long wisteria-like panicles which drape from branch and twig tips.

Yellowwood may bloom 2 to 3 consecutive years and not flower again for 1 to 2 years. The triggering mechanism for flowering is not clearly understood. A complex of environmental and physiological factors may be involved.

Over the past two decades the weather across the Southern Appalachian region can only be described as “extreme”, unusually dry, hot summers and unseasonably mild winters. A physiological condition called “biennial bearing” may be in play here. If a tree sets an unusually heavy seed load one summer, few to no flowers are initiated the following spring.

Whether it flowers or not, yellowwood makes a fine landscape shade tree for any sized landscape. Plant in well drained, slightly acidic soil in full sunlight. Its dark green compound leaves remain pest free from spring until early autumn. Yellowwood’s bright yellow fall color arrives at a time when many trees have already defoliated. Its smooth gray colored bark is very beech-like and has multi-seasonal interest.

Summer Wine™: The Taming of The Ninebark

Posted by Hugh on May 19th, 2011

Physocarpus 'Summer Wine'

Over the past 25 years our native Eastern ninebark (Physocarpus opulifolius) has been reborn. Its overly vigorous nature has been tamed. Latest up is Summer Wine™ ninebark with small, deeply cut, wine burgundy leaves, quite different from the medium green foliage of old-fashioned ninebarks. Summer Wine is a more compact (5-6 feet in height and width) grower.

Grow ninebark in full sun to retain its reddish leaf color longer. Ninebark grows in any soil type, tolerates wet soggy ground, and is pH insensitive. It demonstrates exceptional heat and drought tolerance after one year in the garden. Annual pruning, right after spring flowers have faded, further limits growth and presents many design choices.

Summer Wine fits a multiple of landscape uses: grouped enmasse as a dense growing deciduous hedge, screen or border, or grown by itself as a landscape specimen or in a patio container. Ninebark grown in outdoor containers is winter hardy here in the Southern Appalachian region (USDA zones 6 and 7).

White spirea-like flower clusters, 1 ½ – 2 inch wide, open in May. White blossoms and dark foliage playoff each other. The reddish leaf tint has bled out by mid-summer, now dark green and usually blemish-free. Autumn leaf color is of no consequence.

Select Hollies for Privacy

Posted by Hugh on May 16th, 2011

: Ilex opaca ‘Greenleaf’

I continue to witness the overplanting of Leyland cypress (Cupressocyparis x leylandii) across the Southern Appalachian region (USDA zones 6 and 7). This is followed by Japanese cedar (Cryptomeria japonica) and western arborvitae (Thuja x plicata). These three evergreen species have a rapid growth rate and eventually attain heights of 40-60 feet, sometimes in less than 20 years. Ask yourself the question: “do you really need a huge green barrier around your property?”

Hollies offer the benefits of lustrous green foliage and colorful fruit. The following evergreen species create a dependable privacy screen: Dwarf Burford holly (I. cornuta ‘Dwarf Burford’), Inkberry (I. glabra), American holly (I. opaca), Foster #2 holly (I. x attenuata), and Nellie R. Stevens holly (I. x ‘Nellie R. Stevens’).

A few simple tips about growing hollies:

Hollies prefer a slightly acidic, well-drained, and organically rich soil.
Hollies prefer full to partial sun location.
Established hollies demonstrate good drought tolerance.
Space plants a minimum of 12 feet apart.
Hollies should be properly mated. Fruit are produced on female cultivars and a matching male pollinator should be planted.